1 use std::ffi::{CStr, CString};
2 use std::borrow::Cow;
3 use std::os::raw;
4
5 use crate::Error;
6
7 /// Checks for last byte and avoids allocating if it is zero.
8 ///
9 /// Non-last null bytes still result in an error.
cstr_cow_from_bytes(slice: &[u8]) -> Result<Cow<'_, CStr>, Error>10 pub(crate) fn cstr_cow_from_bytes(slice: &[u8]) -> Result<Cow<'_, CStr>, Error> {
11 static ZERO: raw::c_char = 0;
12 Ok(match slice.last() {
13 // Slice out of 0 elements
14 None => unsafe { Cow::Borrowed(CStr::from_ptr(&ZERO)) },
15 // Slice with trailing 0
16 Some(&0) => Cow::Borrowed(CStr::from_bytes_with_nul(slice)
17 .map_err(|source| Error::CreateCStringWithTrailing { source })?),
18 // Slice with no trailing 0
19 Some(_) => Cow::Owned(CString::new(slice)
20 .map_err(|source| Error::CreateCString { source })?),
21 })
22 }
23
24 #[inline]
ensure_compatible_types<T, E>() -> Result<(), Error>25 pub(crate) fn ensure_compatible_types<T, E>() -> Result<(), Error> {
26 if ::std::mem::size_of::<T>() != ::std::mem::size_of::<E>() {
27 Err(Error::IncompatibleSize)
28 } else {
29 Ok(())
30 }
31 }
32